Imaging features of COVID-19: What we can learn from SARS and MERS (Review).

Coronavirus disease 2019 (COVID-19) is a highly infectious type of pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has rapidly become a global pandemic. COVID-19, SARS and Middle East respiratory syndrome (MERS) are all caused by members of the Coronaviridae family. As expected, emerging genetic and clinical evidence from patients with COVID-19 has indicated that the pathway of infection is similar to that of SARS and MERS. Additionally, much like SARS and MERS, chest imaging serves an important role in the diagnosis, management and follow-up of patients with COVID-19. Although these related viruses present a similar pneumonic pathogenesis, the imaging results have distinguishable features. The current review evaluated the imaging results of patients with SARS and MERS and explored the potential similarities and differences among patients with COVID-19, SARS and MERS at early, progressive, severe and recovery stages, with the aim of improving our understanding of SARS-CoV-2 infections by comparing the features of COVID-19 images with those of SARS and MERS. The current review assessed whether imaging results had implications for the administration of corticosteroids as treatment for COVID-19. Whether corticosteroids can inhibit inflammatory cytokine storms and reduce the mortality of patients with viral pneumonia remains controversial. However, his review may help radiologists and clinicians to identify viral pneumonia and guide appropriate COVID-19 treatment.

rBPI21 (Opebacan) Promotes Rapid Trilineage Hematopoietic Recovery in a Murine Model of High-Dose Total Body Irradiation.

The complexity of providing adequate care after radiation exposure has drawn increasing attention. While most therapeutic development has focused on improving survival at lethal radiation doses, acute hematopoietic syndrome (AHS) occurs at substantially lower exposures. Thus, it is likely that a large proportion of such a radiation-exposed population will manifest AHS of variable degree and that the medical and socioeconomic costs of AHS will accrue. Here, we examined the potential of rBPI21 (opebacan), used without supportive care, to accelerate hematopoietic recovery after radiation where expected survival was substantial (42-75%) at 30 days). rBPI21 administration was associated with accelerated recovery of hematopoietic precursors and normal marrow cellularity, with increases in megakaryocyte numbers particularly marked. This translated into attaining normal trilineage peripheral blood counts 2-3 weeks earlier than controls. Elevations of hematopoietic growth factors observed in plasma and the marrow microenvironment suggest the mechanism is likely multifactorial and not confined to known endotoxin-neutralizing and cytokine down-modulating activities of rBPI21 . These observations deserve further exploration in radiation models and other settings where inadequate hematopoiesis is a prominent feature. These experiments also model the potential of therapeutics to limit the allocation of scarce resources after catastrophic exposures as an endpoint independent of lethality mitigation. This article is protected by copyright. All rights reserved.

Pivotal role of NOD2 in inflammatory processes affecting atherosclerosis and periodontal bone loss.

The purpose of this study was to elucidate the role of nucleotide binding oligomerization domain-containing protein 2 (NOD2) signaling in atherosclerosis and periodontal bone loss using an Apolipoprotein E(-/-) (ApoE(-/-)) mouse model based on the proposed role of NOD2 in inflammation. NOD2(-/-)ApoE(-/-) and ApoE(-/-) mice fed a standard chow diet were given an oral gavage of Porphyromonas gingivalis for 15 wk. NOD2(-/-)ApoE(-/-) mice exhibited significant increases in inflammatory cytokines, alveolar bone loss, cholesterol, and atherosclerotic lesions in the aorta and the heart compared with ApoE(-/-) mice. In contrast, ApoE(-/-) mice injected i.p. with Muramyl DiPeptide (MDP) to stimulate NOD2 and given an oral gavage of P. gingivalis displayed a reduction of serum inflammatory cytokines, alveolar bone loss, cholesterol, and atherosclerotic lesions in the aorta and aortic sinus compared with ApoE(-/-) mice orally challenged but injected with saline. A reduction in body weight gain was observed in ApoE(-/-) mice fed a high-fat diet (HFD) and injected with MDP compared with ApoE(-/-) mice fed a high-fat diet but injected with saline. MDP treatment of bone marrow-derived macrophages incubated with P. gingivalis increased mRNA expressions of NOD2, Toll-like receptor 2, myeloid differentiation primary response gene 88, and receptor-interacting protein-2 but reduced the expressions of inhibitor of NF-κB kinase-ß, NF-κB, c-Jun N-terminal kinase 3, and TNF-α protein levels compared with saline control, highlighting pathways involved in MDP antiinflammatory effects. MDP activation of NOD2 should be considered in the treatment of inflammatory processes affecting atherosclerosis, periodontal bone loss ,and possibly, diet-induced weight gain.

Novel transcriptional regulation of VEGF in inflammatory processes.

Vascular endothelial growth factor (VEGF) is a critical angiogenic factor affecting endothelial cells, inflammatory cells and neuronal cells. In addition to its well-defined positive role in wound healing, pathological roles for VEGF have been described in cancer and inflammatory diseases (i.e. atherosclerosis, rheumatoid arthritis, inflammatory bowel disease and osteoarthritis). Recently, we showed that transcription factors LITAF and STAT6B affected the inflammatory response. This study builds upon our previous results in testing the role of mouse LITAF and STAT6B in the regulation of VEGF-mediated processes. Cells cotransfected with a series of VEGF promoter deletions along with truncated forms of mLITAF and/or mSTAT6B identified a DNA binding site (between -338 and -305 upstream of the transcription site) important in LITAF and/or STAT6B-mediated transcriptional regulation of VEGF. LITAF and STAT6B corresponding protein sites were identified. In addition, siRNA-mediated knockdown of mLITAF and/or mSTAT6B leads to significant reduction in VEGF mRNA levels and inhibits LPS-induced VEGF secretion in mouse RAW 264.7 cells. Furthermore, VEGF treatment of mouse macrophage or endothelial cells induces LITAF/STAT6B nuclear translocation and cell migration. To translate these observations in vivo, VEGF164-soaked matrigel were implanted in whole-body LITAF-deficient animals (TamLITAF(-/-) ), wild-type mice silenced for STAT6B, and in respective control animals. Vessel formation was found significantly reduced in TamLITAF(-/-) as well as in STAT6B-silenced wild-type animals compared with control animals. The present data demonstrate that VEGF regulation by LITAF and/or STAT6B is important in angiogenesis signalling pathways and may be a useful target in the treatment of VEGF diseases.

Receptor activator of nuclear factor kappa B ligand antagonists inhibit tissue inflammation and bone loss in experimental periodontitis.

AIM: The purpose of this study was to assess the role of anti-bone resorptive agents and an anti-inflammatory compound in murine Porphyromonas gingivalis (P. gingivalis)-induced periodontitis. MATERIAL AND METHODS: Six randomly assigned groups were administered vehicle (saline, control) (n = 6), P. gingivalis infection only (untreated) (n = 6), human-Fc (n = 4), Kavain (n = 6), OPG-Fc (n = 6) and Receptor activator of nuclear factor-kappa B (RANK)-Fc (n = 6) intraperitoneally at day 0, 3 and 7. Animals were euthanized on day 10 and subjected to comprehensive histomorphometric analysis. To capture the progress of inflammation, serum samples were collected at days 0, 3, 7 and 10 for levels of pro-inflammatory cytokines. RESULTS: Compared with control group, OPG-Fc, RANK-Fc and Kavain treatment showed significant bone loss reduction with OPG-Fc performing better than RANK-Fc or Kavain. Epithelial down-growth showed significant reduction in treatment groups with OPG-Fc performing better than RANK-Fc or Kavain. Finally, Kavain, OPG-Fc and RANK-Fc-treated mice displayed reduced inflammatory cell counts and cytokine expression particularly at day 7 postinfection. CONCLUSIONS: RANKL antagonists and Kavain effectively reduced alveolar bone loss in P. gingivalis-induced periodontitis in our mice model. Compared with RANK-Fc, Kavain-treated animals showed milder improvement of bone and connective tissue inflammation. Therapeutic implications in the prevention of periodontal bone loss are discussed.

Blood protein profiles of infants born before 28 weeks differ by pregnancy complication.

OBJECTIVE: Disorders that lead to preterm delivery influence the fetal inflammatory response. STUDY DESIGN: We calculated odds ratios of elevated concentrations of 25 blood proteins on the first postnatal day in 798 infants born before the 28th week and classified by the pregnancy disorder that lead to preterm delivery. RESULTS: Concentrations of cytokines (IL-1ß, IL-6, TNFα), cytokine receptors (IL-6R, TNF-R1, TNF-R2), systemic inflammatory proteins (CRP, SAA, MPO), chemokines (IL-8, MCP-1, MCP-4, MIP-1ß, RANTES, I-TAC), adhesion molecules (ICAM-1, ICAM-3, VCAM-1, E-selectin), and metalloproteinases (MMP-1, MMP-9) were elevated in children delivered after preterm labor, membrane rupture, abruption, and cervical insufficiency, whereas such a pattern was not seen after preeclampsia or fetal indication/growth restriction. Inflammatory profiles were also associated with maternal vaginitis. CONCLUSION: The patterns of blood proteins in the newborn support the division of pregnancy disorders that lead to preterm delivery into those associated, and those not associated, with inflammation.

Treating triple-negative breast cancer by a combination of rapamycin and cyclophosphamide: an in vivo bioluminescence imaging study.

Rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, has been shown to inhibit the growth of oestrogen positive breast cancer. However, triple-negative (TN) breast cancer is resistant to rapamycin treatment in vitro. We set to test a combination treatment of rapamycin with DNA-damage agent, cyclophosphamide, in a TN breast cancer model. By binding to and disrupting cellular DNA, cyclophosphamide kills cells via interfering with their normal functions. We assessed the responses of nude mice bearing tumour xenografts of TN MDA-MB-231 cells to the combination of rapamycin and cyclophosphamide in both orthotopic mammary and lung-metastasis models. We tracked tumour growth and metastasis by bioluminescent imaging and examined the expression of Ki67, CD34 and HIF-1alpha in tumour tissues by immunohistochemistry and apoptosis index with TUNEL assay, and found that MDA-MB-231 cells are sensitive to rapamycin therapy in orthotopic mammary, but not in lung with metastasis. Rapamycin when combined with cyclophosphamide is found to have a more significant effect in reducing tumour volume and metastasis with a much improved survival rate. Our data also show that the sensitivity of TN tumours to rapamycin is associated with the microenvironment of the tumour cells. The data indicate that in a relatively hypoxic environment HIF-1alpha may play a role in mediating the anti-cancer effect of rapamycin and cyclophosphamide may prevent the feedback activation of Akt by rapamycin. Overall our results show that rapamycin plus cyclophosphamide can achieve an improved efficacy in suppressing tumour growth and metastasis, suggesting that the combination therapy can be a promising treatment option for TN cancer.

Identification of a GH110 subfamily of alpha 1,3-galactosidases: novel enzymes for removal of the alpha 3Gal xenotransplantation antigen.

In search of alpha-galactosidases with improved kinetic properties for removal of the immunodominant alpha1,3-linked galactose residues of blood group B antigens, we recently identified a novel prokaryotic family of alpha-galactosidases (CAZy GH110) with highly restricted substrate specificity and neutral pH optimum (Liu, Q. P., Sulzenbacher, G., Yuan, H., Bennett, E. P., Pietz, G., Saunders, K., Spence, J., Nudelman, E., Levery, S. B., White, T., Neveu, J. M., Lane, W. S., Bourne, Y., Olsson, M. L., Henrissat, B., and Clausen, H. (2007) Nat. Biotechnol. 25, 454-464). One member of this family from Bacteroides fragilis had exquisite substrate specificity for the branched blood group B structure Galalpha1-3(Fucalpha1-2)Gal, whereas linear oligosaccharides terminated by alpha1,3-linked galactose such as the immunodominant xenotransplantation epitope Galalpha1-3Galbeta1-4GlcNAc did not serve as substrates. Here we demonstrate the existence of two distinct subfamilies of GH110 in B. fragilis and thetaiotaomicron strains. Members of one subfamily have exclusive specificity for the branched blood group B structures, whereas members of a newly identified subfamily represent linkage specific alpha1,3-galactosidases that act equally well on both branched blood group B and linear alpha1,3Gal structures. We determined by one-dimensional (1)H NMR spectroscopy that GH110 enzymes function with an inverting mechanism, which is in striking contrast to all other known alpha-galactosidases that use a retaining mechanism. The novel GH110 subfamily offers enzymes with highly improved performance in enzymatic removal of the immunodominant alpha3Gal xenotransplantation epitope.

Bacterial glycosidases for the production of universal red blood cells.

Enzymatic removal of blood group ABO antigens to develop universal red blood cells (RBCs) was a pioneering vision originally proposed more than 25 years ago. Although the feasibility of this approach was demonstrated in clinical trials for group B RBCs, a major obstacle in translating this technology to clinical practice has been the lack of efficient glycosidase enzymes. Here we report two bacterial glycosidase gene families that provide enzymes capable of efficient removal of A and B antigens at neutral pH with low consumption of recombinant enzymes. The crystal structure of a member of the alpha-N-acetylgalactosaminidase family reveals an unusual catalytic mechanism involving NAD+. The enzymatic conversion processes we describe hold promise for achieving the goal of producing universal RBCs, which would improve the blood supply while enhancing the safety of clinical transfusions.

Nephrin and podocin dissociate at the onset of proteinuria in experimental membranous nephropathy.

BACKGROUND: The slit diaphragm plays a critical role in maintaining the barrier function of the glomerular capillary wall. The pathogenic mechanism of proteinuria in membranous nephropathy remains uncertain. This study was undertaken to analyze the pathogenic role of slit diaphragm in proteinuria in experimental membranous nephropathy. METHODS: The expression and the localization of slit diaphragm-associated molecules (nephrin, podocin, and CD2AP) and other podocyte-associated molecules (podocalyxin and alpha(3) integrin) in passive and active Heymann nephritis were analyzed by immunofluorescence and Western blot analysis. The interaction of slit diaphragm-associated molecules was investigated by the dual-labeling immunofluorescence method. The mRNA expression of these molecules was also analyzed. RESULTS: Shifts in nephrin and podocin staining patterns, from linear to granular, were detected in the early stages of passive Heymann nephritis. These shifts were not parallel, and the dissociation of these molecules was detected by the dual-labeling immunofluorescence method in passive and active Heymann nephritis. Western blot analyses with sequentially solubilized materials indicated that the nephrin-rich fraction changed from being partly detergent-resistant to being predominantly detergent-soluble. This change did not occur with podocin. Nephrin excreted into urine was already detected in the early stages of passive Heymann nephritis. Decreased mRNA expression of nephrin and podocin was observed before the onset of proteinuria. By contrast, no extensive change in the expression of alpha(3) integrin was observed in this study. CONCLUSION: Nephrin is dissociated from podocin and excreted into urine in the early stages of Heymann nephritis. The reduced expression of nephrin and podocin, along with their dissociation, may contribute to the development of proteinuria in Heymann nephritis.

Podocyte slit-diaphragm protein nephrin is linked to the actin cytoskeleton.

Nephrin is an Ig-like transmembrane protein. It is a major component of the podocyte slit diaphragm and is essential for maintaining normal glomerular permeability. CD2-associated protein (CD2AP) is also necessary for normal glomerular permeability and is a putative nephrin adapter molecule. Here, we document that nephrin and CD2AP are linked to the actin cytoskeleton. As detected by Western blot analysis, nephrin and CD2AP were both insoluble when cell membranes from normal rat glomeruli were extracted with 0.5% Triton X-100 (TX-100) at 4 degrees C in the presence of divalent cations, but they were solubilized when the extraction included potassium iodide (KI) to depolymerize F-actin. In addition, a small fraction of the solubilized nephrin and CD2AP was recovered in the low-density fractions of OptiPrep flotation gradients, which indicates that a portion of nephrin, possibly associated with CD2AP, resides in a cholesterol- or sphingolipid-rich region of the plasma membrane. Immunofluorescent staining of unfixed sections of normal rat kidney for nephrin, CD2AP, and F-actin was unaltered by treatment with TX-100 but was greatly diminished by addition of KI. Nephrin staining was slightly reduced by cholesterol depletion with methyl-beta-cyclodextrin in the presence of TX-100 but was nearly absent after addition of KI. These results document that nephrin anchors the slit diaphragm to the actin cytoskeleton, possibly by linkage to CD2AP, and that nephrin traverses a relatively cholesterol-poor region of the podocyte plasma membrane. In addition, a small pool of actin-associated nephrin and CD2AP resides in lipid rafts, possibly in the cholesterol-rich apical region of the podocyte-foot processes.

Nephrin dissociates from actin, and its expression is reduced in early experimental membranous nephropathy.

These studies examined the expression of the podocyte slit diaphragm protein nephrin and its association with actin at the onset of proteinuria in passive Heymann nephritis (PHN), a rat model of human membranous nephropathy. Four days after immunization, 58% of PHN rats had mild proteinuria. At that time, most slit diaphragms were still visible on electron microscopy; however, in those locations where the deposits encroached on the filtration slits, the slit diaphragms were either displaced or absent. On day 7, the PHN rats were severely proteinuric, and most slit diaphragms were either absent, displaced, or replaced by occluding-type junctions. Immunofluorescence microscopy with antibodies to the external and cytoplasmic domains of nephrin showed a progressive loss of staining and a change in the distribution of nephrin from an interrupted linear pattern in normal controls to a more dispersed and clustered pattern in PHN. In contrast, the intensity of staining for ZO-1 and CD2-associated protein (CD2AP), two other proteins that are located on the cytoplasmic face of the slit diaphragm, was undiminished. Immunogold electron microscopy confirmed the progressive disappearance of nephrin from podocyte foot processes and retention of CD2AP. Glomeruli and glomerular cell membranes were extracted sequentially with Triton X-100, followed by DNase I or potassium iodide to depolymerize actin. Western blot analysis of the extracts showed a progressive decline of total nephrin on days 4 and 7 of PHN as well as a reduction in the actin-associated fraction. These findings show that nephrin partly dissociates from actin at the onset of podocyte injury in PHN. This is accompanied by a progressive loss of nephrin from the podocyte foot processes and prominent changes in the morphology of the slit diaphragms. These events may underlie the loss of podocyte barrier function in membranous nephropathy.